259 lines
8.8 KiB
C++
259 lines
8.8 KiB
C++
/** @file token.cpp
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*
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* author: Roland Conybeare
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**/
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#include "Token.hpp"
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#include "xo/indentlog/print/tag.hpp"
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namespace xo {
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namespace scm {
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bool
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Token::bool_value() const
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{
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if (tk_type_ != tokentype::tk_bool) {
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throw (std::runtime_error
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(tostr("token::bool_value",
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": token with type tk found where tk_bool expected",
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xtag("tk", tk_type_))));
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}
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if (text_ == "true")
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return true;
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if (text_ == "false")
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return false;
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throw (std::runtime_error
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(tostr("token::bool_value",
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": unexpected input string tk_bool token",
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xtag("text", text_))));
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return false;
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}
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std::int64_t
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Token::i64_value() const
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{
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if (tk_type_ != tokentype::tk_i64) {
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throw (std::runtime_error
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(tostr("token::i64_value",
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": token with type tk found where tk_i64 expected",
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xtag("tk", tk_type_))));
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}
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if (text_.empty()) {
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throw (std::runtime_error
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(tostr("token::i64_value",
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": unexpected empty input string for tk_i64 token")));
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}
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int sign = 1;
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int value = 0;
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{
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auto ix = text_.begin();
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auto end_ix = text_.end();
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char ch = *ix;
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if (ch == '+') {
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++ix;
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} else if (ch == '-') {
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sign = -1;
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++ix;
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}
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if (ix == end_ix) {
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throw (std::runtime_error
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(tostr("token::i64_value",
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": input text found where at least one digit expected",
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xtag("text", text_))));
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}
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for (; ix != end_ix; ++ix) {
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char ch = *ix;
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if ((ch >= '0') && (ch <= '9')) {
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value *= 10;
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value += (ch - '0');
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} else {
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throw (std::runtime_error
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(tostr("token::i64_value",
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": unexpected char ch in integer token",
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xtag("ch", ch))));
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}
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}
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}
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return sign * value;
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} /*i64_value*/
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double
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Token::f64_value() const
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{
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if (tk_type_ != tokentype::tk_f64) {
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throw (std::runtime_error
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(tostr("token::f64_value",
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": token with type tk found where tk_f64 expected",
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xtag("tk", tk_type_))));
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}
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if (text_.empty()) {
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throw (std::runtime_error
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(tostr("token::f64_value",
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": unexpected empty input string for tk_f64 token")));
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}
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int sign = 1;
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/* integer representing denormalized unsigned mantissa
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* (mantissa scaled by smallest power of 10 sufficient to make
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* it an integer)
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*/
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std::int64_t mantissa = 0;
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/* counts #of digits to the right of decimal point '.' */
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int rh_digits = 0;
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/* sign of exponent */
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int exp_sign = 1;
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/* value of exponenct = integer to the right of 'e' or 'E' */
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int exponent = 0;
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/* floating-point value will represent
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* sign * mantissa * 10^(sign*exponent - rh_digits)
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*/
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{
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auto ix = text_.begin();
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auto end_ix = text_.end();
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char ch = *ix;
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if (ch == '+') {
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++ix;
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} else if (ch == '-') {
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sign = -1;
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++ix;
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}
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if (ix == end_ix) {
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throw (std::runtime_error
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(tostr("token::f64_value",
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": input text found where at least one digit expected",
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xtag("text", text_))));
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}
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/* true iff decimal point '.' present in mantissa */
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bool have_decimal_point = false;
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/* true iff exponent prefix 'e' or 'E' present */
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//bool have_exponent = false;
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/* counts number of digits in mantissa
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* (both before and after, but not including, any decimal point
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*/
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int m_digits = 0;
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/* digits to the left of decimal point */
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int lh_digits = 0;
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/* loop over mantissa digits */
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for (; ix != end_ix; ++ix) {
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char ch = *ix;
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if (ch == '.') {
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if (have_decimal_point) {
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throw (std::runtime_error
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(tostr("token::f64_value",
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": input text found where at most one decimal point expected",
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xtag("text", text_))));
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}
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have_decimal_point = true;
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lh_digits = m_digits;
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} else if ((ch >= '0') && (ch <= '9')) {
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mantissa *= 10;
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mantissa += (ch - '0');
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++m_digits;
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} else if (ch == 'e' || ch == 'E') {
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//have_exponent = true;
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break; // done with mantissa
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} else {
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throw (std::runtime_error
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(tostr("token::i64_value",
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": unexpected char ch in integer token",
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xtag("ch", ch))));
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}
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}
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if (have_decimal_point)
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rh_digits = m_digits - lh_digits;
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if (ix != end_ix) {
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/* continue to read exponent */
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/* skip e|E */
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++ix;
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if (ix == end_ix) {
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throw (std::runtime_error
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(tostr("token::f64_value",
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": on input text, expect at least one digit following exponent marker e|E",
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xtag("text", text_))));
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}
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char ch = *ix;
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if (ch == '+') {
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++ix; /*skip*/
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} else if (ch == '-') {
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exp_sign = -1;
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++ix;
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}
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for (; ix != end_ix; ++ix) {
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char ch = *ix;
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if ((ch >= '0') && (ch <= '9')) {
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exponent *= 10;
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exponent += (ch - '0');
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} else {
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throw (std::runtime_error
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(tostr("token::f64_value",
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"; on input text, expect only digits following"
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" (possibly signed) exponenct marker",
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xtag("text", text_))));
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}
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}
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}
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}
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/* floating-point value will represent
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* sign * mantissa * 10^(sign*exponent - rh_digits)
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*/
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double mantissa_f64 = sign * mantissa;
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#ifdef OBSOLETE_DEBUG
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std::cerr << xtag("text", text_)
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<< xtag("rh_digits", rh_digits)
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<< xtag("mantissa_f64", mantissa_f64)
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<< xtag("exp_sign", exp_sign)
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<< xtag("exponent", exponent)
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<< std::endl;
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#endif
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double retval = (mantissa_f64
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* detail::pow10((exp_sign * exponent)
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- rh_digits));
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return retval;
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} /*f64_value*/
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void
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Token::print(std::ostream & os) const
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{
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os << "<token"
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<< xtag("type", tk_type_);
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if (has_variable_text())
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os << xtag("text", text_);
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os << ">";
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} /*print*/
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} /*namespace scm*/
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} /*namespace xo*/
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/* end token.cpp */
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